Cyanine dyestuff



Patented Dec. 7, 1948 GYANINE DYESTUFF J 011:: David Kendall,- Harold Gordon Suggate, and Henry Walter Wood, Ilford, England, assignors to Ilfor Limi e I f Eng nd, a Br tish company No Drawing- Application January 8, 1942, Serial NO- 426,098, In Great Britain January 17, 19.41

.2 Claims.- 269-24 This invention relates to the produ ti n nd use of dyestufis useful for sensitising photor graphic silver halide emulsions.

In our co-pending application Serial NO,.f1Z 6,097 filed on even date herewith, now patent No, 2,368,222, dated January 30, 1945, there is described the production of compounds of the generalFormulaI where X is an oxygen atom, a sulphur atom or .a lenium atom, A is the residue of .a substituted or unsubstituted mono ,or polyacarbocyclic nu.- cleus, R1, R2 and R3 are hydro en atoms or hydro-,- carbon groups and n is a positive integer greater than 1.

According to the present invention sensitising dyestuffs for photographic silver halide emulsions are prepared by condensing an alkyl or aralkyl quaternary salt of a compound of neral Form a I with an alkyl or .a-ralkyl quaternary salt of a heterocycl nitrogen compound containing, in the a .or 7 position to a heterocyclic nitrogen atom, a thioetheror selenoether groupin \(i'noluding an aryl-, alkylor .aralkyl-thioether group or a corresponding .seleno-ether group o a -CH=CH xNH2 group wherezc is 1 210 -3 (in. eluding N-acyl, N-aryl and Nfia qylfi e fxl .substia tutedgroups of this typ The gro ping CHQH aNH2 ,is v.her im te referred to as the aminovinyl :typ of group.

The condensation is dependent on the reactivity of the CH2 group shewn at the right-hand end of general Formula I and theproducts conform to the general Formula II.

Where1X,.,A, R1, R2, R3 and have the meanings assigned to th m above, B and R5 are alkyl or aralkyl groups, 3 is nought or a small positiiezios teger, e. g, 1 or '2, a is nought or .1, B is an acid e idue a d D is the esidue f a h eros ic nitr en compound of t type sed in yan n dyes,-

Th r s du .A may be, fo e ample a ben ene or naphthalene, anthracene or phenanthrene group which may or may not itself be substituted, e. g, by halogen atoms or alkyl, aryl, substituted aryl, aral syl, substit ted a lky ami s t u no a l xy a y x o ca b vl r ups.

s stated a ove, h roup R1 R2 a B: m e hydro en or h d rbo ro p Th the y be alkyl, aralkyl or aryl groups, e. a. methyl, ethyl, propyl and higher alkyl groups, benzyl and naphthyl-methyl groups and phenyl, naphthyl and homologous aryl groups. The groups R4 and R are alkyl or aralkyl roups a d may be, for example, any of specific alkyl and aralkyl groups referred to above.

D in the foregoing Formula II is the residue of a heterocyclic nitrogen com-pound. Examples of suitable heterocyelic nitrogen compounds are: substituted or unsubstituted thiazoles, thiazolines, oxazoles, oxazolines, selenoazoles, selenoazolines, pyridine, quinoline, indolenine, diazines (e. g. pyrimidine) thiodiazoles and quinazoline and the corresponding sutstituted or unsubstituted polycyclic compounds such as benzthiazoles, naph thathiazoles and anthrathiazoles and the corresponding polycyclic oxazoles and selenazoles and also the diazines described in British Patent speci fication No. 425,609.

As already indicated, the process of this invention consists-in a reaction between the quaternary salts. The salt groups may be the same or difiernt a y e, for e am le, chlor de, b om de od d su phate o perchlorate ou sre erably, ho e r the reactin quater ar lt are a kyl or re ky -p-to u n suluhonat s, se.- ethy r methrl-n-tolm su phonate.

In carrying out the process of the -invention, it isnot necessary .to isolate the quaternary salts ,of the two r actan b-y cond s a compound of general Formula :I with a :heterocyclic nitrogen base containing the said reactive thioether, seleno-ether or aminovinyl group, together with sufficient alkylior arallsyl saltto convert both reactants to quaternary salts, the reaction may e eflected in one stage. ,A particularly convenient p o e s is to em loy an a ky or ral v toluene ,sulphonate and to efiec-t the reaction by fusing together the compound of Formula I, the hete oqyo io nit ogen base cont in n t e specifiled re ctive g oup and 1 su fiei noy ,of alkyl or 1 3 aralkyl-p-toluene sulphonate to convert both the reactants to quaternary salts.

Preferably, the condensation process of this invention is completed, in the presence of an acidbinding agent, e. g. pyridine, piperidine, triethylamine, sodium acetate or sodium carbonate,

The following examples illustrate the invention but are not to be regarded as limiting it in any way:

EXAMPLE I 2.2'- dimethyl-7.9 dimethylenethiaoxacarbocyanine iodide 0.92 gm. of 1'-(A )-cyclopentenyl benzoxazole, 0.95 gm. of l-methylthiol benzthiazole and 1:95 gms. of methyl-p-toluene sulphonate weremixed together and fused for 3 /2 hours at 140 C. The mixture was then allowed to cool, 15 cos. of pyridine were added and the mixture then warmed to dissolve the solid and then heated at a gentle boil for half-an-hour. The resulting solution was poured into a warm solution of 6 gms. of potassium iodide. A precipitate formed and this was separated by filtration, washed successively with ethyl alcohol, water, benzene and ether and then recrystallised from methyl alcohol. The product was thus obtained as minute green crystals, melting at 262 C. with decomposition. This dyestuff when included in a silver iodo bromide emulsion imparts a band of sensitivity extending to 6900 A. with a maximum at 6700 A. When included in a silver chloride emulsion it imparts a band of sensitivity between 5400 A. and 6300 A. with a maximum at about 6000 A.

EXAMPLE II 2.2-dimeth /Z-7.9-dimethyle1ie-5'.6- benzorracarbocyanine iodide This dyestuff was prepared by a method similar to that described in Example I using 0.92 gm. of 1-(A -cyclopentenyl benzoxazole, 1.1 gms. of 2-methylthiol-5.6-naphthoxazole, 1.95 gms. of methyl-p-toluene sulphonate, 15 gms. of pyridine and a solution of 6 gms. of potassium iodide. The product was obtained as a slate-coloured mass of minute crystals, melting at 242 C. with decomposition. This dyestuff when included in a silver iodobromide emulsion imparts a band of sensitivity extending to 6500 A. with a maximum at 5850 A.

EXAMPLE III EXAMPLE IV 2.3 -dimethyl-7 .9-dimethylene- -methylthiolpp-thiodiazole-oxacarbocyanine iodide A dystufi' was prepared by a method similar to that described in Example I using 0.61 gm. of 1-(A -cyclo-pentenyl benzoxazole, 0.79 gm. of dimethylthiol-oe-thiadiazole, 1.44 gms. of methyl-p-toluene sulphonate and 10 cos. of pyridine. The product was obtained as dark green 4 crystals, melting at 249-250 C. This dyestuif when included in a silver chloride emulsion imparts a band of sensitivity extending from 5100 A. to 6400 A. with.a maximuiii'at 6000 A.

EXAMPLE V 2.2'-dimethyl-7.9-trimethyZene-oxathiacarbocyanine iodide cooling, deposited the dyestuii in crystalline form. The crude product thus obtained was washed with hot benzene and recrystallised from methyl alcohol. The product was thus obtained as small dark blue crystals melting at 256 C. with decomposition.

The dyestufi when included in a silver iodobromide emulsion imparts a band of sensitivity extending to 6600 A. with a maximum at 6200 A.

EXAMPLE VI Z-methyZ-Z-ethyl-7.9-trimethylene-oxathiacarbocycmine iodide This dyestufi was prepared by a method sim- N-ethyl-benzthiazole-thione, 2.5 gms. of methylp-toluene sulphonate and 12 cos. of pyridine. The product was thus obtained as small dark green crystals melting at 225 C. with decomposition.

This dyestufi when included in a silver iodobromide emulsion imparts a band of sensitivity extending to 6800 A. with a broad maximum at EXAMPLE VII 2.2-dimethyl-7.9-trimethylene-thiacarbocyanine bromide obtained as small dark green crystals, melting at 234 C. with decomposition.

This dyestuff when included in a silver iodobromide emulsion imparts a band of sensitivity gxtenging to 7000 A. with a broad maximum at EXAMPLE VIII 2 methyl 2 ethyl 7.9 trimethylene thiacarbocyanine iodide This dyestufl was prepared by a method similar to that employed in Example V using 1.07 gms. of 1-(A -cyclohexenyl-benzthiazole, 1.4 gms. of N-ethyl-benzthiazole thione, 2.5 ms. of methyl- .p-toluene sulphonate and 12 cos. of pyridine. The product was obtained as small dark green crystals, melting at 275 C. with decomposition.

This dyestufi when included in a silver iodobromide emulsion imparts a band of sensitivityby extending to 6900A. with a maximum at This dyestulf was prepared by a method similar to that employedin Example v using 107 gm. of 1-(A ).-cyclohexenyl benzthiazole, 0.95 gm. of 2-methylthiol quinoline, 2.0 ms. of methyL-ptoluene sulphonate and 12 cos. of pyridine. The product was obtained as small dark green crystals, melting at 270 C. with de. mposition.

EXAMPLE X 2.1 -dimethyl-7.9-trimethylene thz'e-indo-(I .2 di-carbocyam'ne iodide 1.07 gms. of 1-(A ).-cyclohexenyl benzthiazole and 0.93 gm. of methyl-p-toluene sulphonate were fused together at 150-160 C. for 3 hours. The salt thus obtained was dissolved in 15 cos. of pyridine, 2.23 guns. of z-weaoetanilidovinyl. 1.33-trimethylindolenium iodide was. added. and the mixture refluxed gently for twenty minutes. The resulting solution was poured into a warm solution of potassium iodide. On cooling an oil separated from which a solid dyestufi Was obtained by treatment with ethyl alcohol. The dyestuff was recrystallised from methyl alcohol and thus obtained as green crystals with a golden reflex melting at 38 C. with decomposition.

This dyestufi when included in a silver iodobromide emulsion imparts a band of sensitivity from 6000 A. to 7400 A. with a maximum at 7000 A.

E AMPLE XI Z-methyl-Z-ethl/Z-7.9 trimethylene thia-dicarbocyamne iodide 0.8 gm. of 1-(A )-.cyclohex enyl .benzthiazole and 0.75 gm. of methybp tolueme sulphonate were fused together at 140-150 C. for 3% hours. The quaternary salt thus obtained was dissolved in ccs. of pyridine, 1.2 gins. of l-w-acetanilidovinyl-2-ethyl benzthiazole iodide was added and the mixture refluxed gently for 20 minutes. The resulting solution waspoured into a warm solution of potassium iodide and on cooling the dyestuff crystallised out. It was separated by filtration, recrystallised from methyl alcohol and thus obtained as bluish green crystals, melting. at 243 C. with decomposition.

This dyestufi when included in a silver iodobromide emulsion imparts a band of sensitivity from 0000 A. to 7800 A. with a maximum at EXAMPLE XII 2.2'.4.S-tetramethyl-7.Q-dimethyleneihiaoxoccm bocyanine iodide W when. nul ifi d; in. a il r odo bromide emulsion imparts a band of sensitivityextending to about 6700 A. with a maximum at about 6500 A.

EXAMPLE XIII 2.2' 4.5-tetramethyl-7.9-dimethylene-3.4-be'nzthiaozracarbocy'anine iodide .06 gms. of 4.5-dimethyl 1(A )-cyclopentenyl benzoxazole, 1.16 gins. of l-methylthiol-3.4-naphthathiazole and 2 gms. of methyl-p-toluene sulphonate were mixed together and heated for 5 hours at 160 C. The resulting mixture was slightly cooled, 20 es. of pyridine was added and the Whole was then gently boiled for 30 minutes. It was then poured into aqueous potassium iodide solution and allowed to cool. After dilution with ether, the dyestufl' separated as black crystals. These were removed by filtration and washed with water, ethyl alcohol, benzene and ether. This dyestufi when included in a silver iodo bromide emulsion imparts a band of sensitivity extending to about 7000 A. with maximum at about 6200 A.

EXAMPLE XIV 2.2-dimethyl 7.9-dimethg/Zene thiacarboeyanine bromide 1 gm.. of 1( )-cyclopentenyl benzthiazole, 0.98 gm. of l-methylthiol benzthiazole and 1.95 gms. of methyl-p-toluene sulphonate were mixed together and heated at -130 C. for 3 hours. 10 cos. of pyridine were then added and the mixture boiled for 20 minutes and then poured into aqueous potassium bromide solution and allowed to cool. The product crystallised out and was filtered off and washed with water, ethyl alcohol and benzene. On recrystallisation from methyl alcohol solution, the product was obtained as black crystals with a green reflex,

' melting at 258-9 C.

This dyestufi when included in a silver iodobromide emulsion imparts a band of sensitivity extending to about 7100 A. with a maximum about 7000 A.

EXAMPLE XV 2.3'-dimethyl-7.9 dimethylene 5 methylthz'olssthiodtazole z'hz'acctrboeyanine bromide 1,0 gm. 1(A )-cyclopentenyl benzthiazole, 1.2

about 6250 A.

EXAMPLE XVI 2.2'-dimethyl 4'.5'-dzmethoxy 7 .Q-dimethylene thiacarbocyzmine bromide 1.0 gm. of MAO-cyclopentenyl benzthiazole, 1.2 gins. 2-methylthiol-eh-dimethoxy benzthiazole and 1.95 gms. methyl-p-toluene sulphonate were mixed together and heated for 3 /2 hours at- 120-130? (3. 20 cos. of pyridine was then added; andthe whole warmed to dissolve the solid matter and then gently boiled for 15 minutes. The solution was then poured into aqueous potassium bromide solution and the dyestufi separated as green crystals, melting at 259-260 C. with decom- EXAMPLE XVII Z-methyZ-1'-ethyl 7.9-trimethylene thiaquino (1.2) dicarbocyam'ne iodide 1.07 gms. of UM) -cyclohexenyl benzthiazole and 0.93 gm. of methyl-p-toluene sulphonate were fused together at 140 C. for 3 hours, and the quaternary salt thus obtained dissolved in 10 cos. pyridine. 1.49 gins. w-acetanilidovinyl quinoline ethiodide was added and the mixture gently refluxed for 20 mins. The solution was then poured into a warm aqueous solution of potassium iodide which, after cooling, was diluted with water. An oil formed which hardened overnight and was recrystallised from methyl alcohol solution, yielding the dyestuff as dark green crystals, melting at 228 C.

This dyestuff when included in a silver iodo bromide emulsion imparts a band of sensitivity extending to about 8200 A. with a maximum at about 7500 A.

EXAMPLE XVIII 2.2-dimethyl-7.9-trimethylene-thia-selenacarbocyanine bromide 1.31 gms. of 1(A )-cyclohexenyl benzselenazole, 0.90 gm. methylthiol benzthiazole and 1.86 gms. methyl-p-toluene sulphonate were fused together at 160 C. for 3 hours and the product refluxed gently with 10 cos. pyridine for 20 minutes. The solution was poured into a warm aqueous solution of potassium bromide and benzene stirred in. The dyestuff crystallised on cooling and was purifled by recrystallising from methyl alcohol solution. It consisted of dark green crystals, melting at 250 C.

All the compounds of the foregoing examples have structural formulae conforming to general Formula II. The system of numbering adopted for the substituent positions in the compounds is as follows: The ring structures are numbered thus Benzoxazole BB-thiodiazole Benzthiazole Benzselenazole 05; /OH; 3 4 a o 8 7 =02 i R 1k Quinoline Indolylidene The methine groups in the conjugated polymethine chain are numbered successively from the heterocyclic grouping to which, in the original intermediate, the cyclopentenyl or similar group is attached. Thus in the case of benzthiazole and similar intermediates where, as indicated above, the numbering goes up to 6, thenext carbon atom in the conjugated chain is 7, the next 8 and so on. The positions of substitution in the heterocyclic grouping which is condensed with the cycloalkylene intermediate are differentiated as 1', 2', etc. Thus the compound of Example I has the formula:

v I I W/ Ca I lHg and the compounds of Examples II, III, V, VI, VII, VIII, XII, XIII, XIV, XVI and XVIII have analogous formulae with variations between benzthiazole, benzoxazoleand the benzselenazole nuclei, between the nature of the substituents in the 2 and 2f. positions,.between the nature of substituents in the carbocyclic rings, and between the number of methylene groups linking the 7 and 9 positions.

The compound of Example IV has the formula:

and a similar numbering of the quinoline ring 45' obtains in the caseof Example XVII.

The compound of Example X has the formula:

l CH: CH: 7 s p 6 CHzGHzCHz 5 7 1 a and the compounds of Examples XI and XVII have analogous formulae with different groups replacing the indolenine group.

As stated above, and as indicated in the foregoing examples, the dyestuffs of this invention are valuable sensitisers for. silver halide photographic emulsions. "I'hey"-m'ay be incorporated in silver halide emulsions of all types, e. g. silver chloride, silver bromide, silver chlorobromide and silver iodobromide emulsions. The quantity of dyestuffs employed for sensitizing will, of course, vary' with the particular purpose for which the emulsion is intended. In general, for a typical emulsion containing'the equivalent of 2% silver, calculated as metal, the proportion may range between 250 and 1250- ccs. of a l'in 2000 solution per litre of emulsion;

In the following claims 'the expressions "thio- I ether group? selenoether group and aminovinyl type of grouphave'been'used for the sake (where a: is 1, 2 01'3) and Ni-acyl, N- aryl and N- acylaryl substituted groups of this type.-

What we claim is:

1. Process for the manufacture of dyestufis which comprises condensing a compound selected from the classconsisting of the alkyl and aralkyl quaternary salts of a compound of thegeneral formula: I

cyanine dyes containing in one of the a and y positions to the heterocyclic nitrogen atom a reactive group selected from the class consistingof the reactive thioether, selenoether and amino vinyl types of group. v p

2. Process according to claim 1' wherein the condensation is efiected in the presence of an acid binding agent.- 7

3. Process for "the manufacture of dyestuiis which comprises condensing a compound of the general formula:

wherein A constitutes the atoms necessary to complete a benzene ring with the two carbon atoms attached to the cyclic atoms X and N, respectively, and form an aromatic hydrocarbon nucleus, X is an atom selected from the class consisting of the oxygen, sulphur and selenium atoms, R1, Rzand R3 are selected from theclass consisting of hydrogen atoms and hydrocarbon groups and n is a small integer greater than 1) with a heterocyclic nitrogen compound of the type used in cyanine dyes containing in one of the or and 7 positions to the heterocyclic nitrogen atom a reactive group selected from the class consisting of the reactive thioether, selenoether and aminovinyi types of group, in the presence of a sumciency of a salt selected from the class consisting of alkyl and aralkyl salts to convert both the said compounds to quaternary nitrogen salts.

4. Process according to claim 3 wherein the salt employed is an alkyl-p-toluene sulphonate.

5. Process according to claim 3 wherein the condensation is completed by heating :the reaction mixture in the presence of an acid binding agent;

6. Process for the manufacture of dyestuffs which comprises condensing a compound selected from the class consisting of the alkyl and aralkyl quaternary salts of a compound of the general formula:

CH2 CH2 A} Z o o oH,

wherein A constitutes the atoms necessary to complete a benzene'ring with the two carbon atomsattach'edto thecyclic atoms X and N, respectively, and 'form'an aromatic hydrocarbon nucleus, andX'isan atom selected from the class consisting of the oxygen, sulphur and selenium atoms) with a compound selected from the class consisting of the alkyl and araikyl quaternary salts oi heterocyclic nitrogen compounds of the type used in cyanine dyes containing in one of the a and positio'ns'to the heterocyclic nitrogen atom a reactive group selected from the class consisting of the reactive'thioether, selenoetherand amino -vinyl types of group. H

' T'Procss for the "manufacture of dyestuffs which comprises condensing a compound selected from the class consisting of the alkyl and aralkyl quaternary salts of a compound of the general formula:

wherein A. constitutes the atoms necessary to complete a benzene ring with the two carbon atoms attached to the cyclic atoms X and N, respectively, and form an aromatic hydrocarbon nucleusand'X is arr-atom selected from the classconsisting of the oxygen; sulphur and selenium atomsiwith acompound selected from the class general formula? C/ GHQ-CH2 at K \VCH wherein A constitutes the atoms necessary to complete a benzene ring with the two carbon atoms attached to the cyclic atoms X and N, respectively, and form an aromatic hydrocarbon nucleus, and X is an atom selected from the class consisting of the oxygen, sulphur and selenium atoms) with a heterocyclic nitrogen compound of the type used in cyanine dyes containing in one of the or and 7 positions to the heterocyclic nitrogen atoms a reactive group selected from the class consisting of the reactive thioether, selenoether and aminovinyl types of group, in the presence of a sufficiency of a salt selected from the class consisting of alkyl and aralkyl salts to convert it both the said compounds to quaternary. nitrogen salts. y

9. Process for the manufacture or dyestuffs which comprises condensing a compound of the general formula:

wherein A constitutes the atoms necessary to complete a benzene ring with the two carbon atoms attached to the cyclic atoms X and N, respectively, andform an aromatic hydrocarbon nucleus, and X is an atom selected from theclass consisting of the oxygen, sulphur and selenium atoms) with a heterocyclic nitrogen compound of the type used in cyanine dyes containing in one of the on and 7 positions to the heterocyclic nitrogen atom a reactive group selected from the class consisting of the reactive thioether, selenoether and amino-vinyl types of group, in the presence of a sufficiency of a salt selected from the class consisting of alkyl and aralkyl salts to convert both the said compounds to quaternary nitrogen salts.

10. Unsymmetrical dyestuffs of the general formula:

wherein A constitutes the atoms necessary to complete a benzene ring with the two carbon atoms attached to the cyclic atoms X and N, re-, spectively, and form an aromatic hydrocarbon nucleus, and X is an atom selected from the class consisting of the oxygen, sulphur and selenium. atoms, R1, R2 and R3 are selected from the class consisting of hydrogen atoms and hydrocarbon groups and n is a small integer greater than 1, R4 and R5 are groups selected from the class consisting of alkyl and aralkyl groups, 11 is selected from the class consisting of nought and small positive integers, z is selected from the class consisting of nought and one, B is an acid residue and D is the residue of a heterocyclic nitrogen compound of the type used in cyanine dyes, the heterocyclic ring of which D forms a part being different from that of which a: forms a part.

11. Unsymmetrical dyestufis of the general formula:

residue and D is the residue of a heterocyclic,

nitrogen compound of the type used in cyanine dyes, the heterocyclic ring of which D forms a part being different from that of which 2: forms a part.

12. Unsymmetrical dyestufis of the general formula:

wherei'nA constitutes the atoms necessary to complete a benzene ring with the two carbon atoms attached to the cyclic atoms X and N, respectively, and form an aromatic hydrocarbon nucleus, andX is an atom selected from the class consisting of the oxygen, sulphur and selenium atoms, Ri'and R5 are groups selected from the class'consisting of alkyl and aralkyl groups, 1 is selected from the class consisting of nought and small positive integers, z is selected from the class consisting of nought and one, B is an acid residue and D is the residue of a heterocyclic nitrogen compound of the type used in cyanine dyes, the heterocyclic ring of which D forms a part being difierent from that of which :0 forms a-part. 1

JOHN DAVID KENDALL.

HAROLD GORDON SUGGA'I'E. HENRY WALTER WOOD.

REFERENCES CITED The following references are of record in the file of this patent:

1 UNITED STATES PATENTS Number Name Date 2,138,223 Wilmans Nov. 29, 1938 2,170,805 Brooker Aug. 29, 1939 r 2,323,503 Wilson July 6, 1943 2,263,749 White Nov. 25, 1931 OTHER REFERENCES 

